When I use Finder to look at the time machine, on a 6 TB disk, it reports 480 GB for one of the computers being backed up there, and 570 GB for the other one (where I saw the error), and 4.1 TB available. Both of these make sense, based on the contents of the computers they are backups of.

However, I receive the error message Disk is nearly full.

Any ideas?

  • MacBook Pro, macOS 10.12.4
  • Time Machine connects to a Time Capsule that is on the network
  • Which disk is listed in System Preferences > Time Machine? Is it the correct one?
    – oa-
    Commented Apr 19, 2017 at 16:36
  • For clarification, are you backing up two different Macs to one hard drive?
    – Jerry
    Commented Apr 19, 2017 at 16:59
  • In answer to oa- Yes, Pref>TimeMach> points to the correct disk.
    – tonyl
    Commented Apr 20, 2017 at 18:21
  • In answer to Jerry Waller, Yes, two different Macs. The disk is sued for nothing else.
    – tonyl
    Commented Apr 20, 2017 at 18:22

1 Answer 1


There is a discrepancy of what is informed as available space and what actually is available for recording. This is discovered by Time Machine when it tries to save data, so the short answer is corrupted data (in this case, data about how data is stored). Time Machine does a complex kind of backup that is not just a copy, so my suggestion is...

  • Make a copy (better a clone) of the backup and erase the Time Capsule disk - format the volume.
  • Restore the data. Make sure the copy got the "real" size, or the backup might be corrupted as well.
  • To monitor the process once started, it has to end within one hour, or the problem might come back.

In my experience, it was taking longer than one hour, so Time Machine started the second backup before ending the first one, leading to a mess! There is third-part solutions to change the Time Machine frequency (two hours or more).

  • First, thanks for the answer! Second, eugh! if you don't mind my saying so. I think I'll wait a bit, since I haven't any spare drives big enough to hold both of the sparsebundle files on the TC now.
    – tonyl
    Commented Apr 20, 2017 at 18:27
  • I'd take a deep breath before writing this answer because happened to me already. I solved by "kidnaping" my kid's PC so I could move the backups safely. Sorry I don't have a better answer, but as you can see, there isn't much of alternatives. One desperate option is to decrease de volume size so you can create a new temporary partition to move files inside the same HDD, but is not advisable as you might lost it all, that's why I didn't include this alternative in my answer.
    – Gustavo
    Commented Apr 23, 2017 at 21:52
  • Thanks again. I'm still contemplating my course of action. Sorry for your experience; hope the kid wasn't too put out!
    – tonyl
    Commented Apr 24, 2017 at 23:26

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